Optiphoue



W. G. HOUSKEEPER.

OP TIPHONE. APPLICATION FILED OCT. 20,1917- Patented Oct. 28,1919.

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OPTIPHONE.

APPLICATION FiLED OCT- 20, I917.

1,320,866. Patented Oct. 28,1919.

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WILLIAM G. HO'[J'SIK'.Fl1i-l'.ER, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WESTERN ELECTRIC COMPANY, PORATION OF NEW YORK.

INCORPORATED, OF NEW YORK, N. Y., A COR- orrrrnorm.

Specification of Letters Patent.

v Patented Oct. 28, 1919.

Application filed October 20, 1917. Serial No. 197,576.

1 '0 all whom it may concern:

Be it known that 1, WILLIAM G. Hous- KEEPER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Optiphones, of. which the following is a full, clear, concise, and exact description.

This invention has reference to the class i of instruments by which the appreciation of the shape of certain characteristics of an object, due to the efiect of light either emitted thereby or reflected therefrom or transmitted therethrough, may be obtained from the sense of hearing. One application I of this is-that a person who is blind may, be able to see by the aid of the ear or may be enabled to obtain some appreciation of the effect obtained through vision;- The name optiphone has been given to this type of instrument.

The invention is designed more particularly' as an improvement on or substitute for the optiphone described and claimed'in the application of F. C. Brown, Serial No. 112,294, filed July 311, 1916, entitled Optiphone. The invention comprehends a novel apparatus and method for performing the functions-of the. invention there de-- scribed. V

The optiphone-as developed by' Brown,- consists, in one form, of a plurality of -Wheatstone bridges, such .as shown. in

Figure 1 of the accompanying drawing.

Each bridge contains at 86181111111]. cell or crystal in one arm and a resistance in each 1 of the other arms; a mechanical interrupter V and a telephone receiver are placed in series in the indicating circuit so that when the bridge is balanced by adjusting thearms no, sound is produced in the telephone receiver. When, however, a black surface, such as that of ordinary black print," is placed in front of the crystal,-the bridge is unbalanced,- causing a flow of current through the l invention and gain automatically balanced. A seriesf.---.'

ing alined'and placed close to ether. The

rate of interruption is made di erent in the different indicator circuits and a single telephone receiver may be used if desired. If print is passed in front of the crystals of the optiphone in-a general direction at right angles to that in which they are alined, one or more distinct tones are produced in the receiver, the pitch and duration ofwhich are an indication of the form ofa printed letter, which indication the user'soon comes to recognize as characteristic of that particular letter. In this man- 'ner the blind are able to read ordinary d or cellis illuminated by the white back.-

ground of the print being in this case too brief to allow the resistance to return to normal value, It is the object of this invention to provide a substitute for the bridge circuits which will notpresent this defect. I

The inventionwill better understood by reference to the accompanying drawings i'nwhich:' p

f Fig. 1 is asimple Wheatst'one bridge cir cuit of the Brown optiphone;

Fig. 2 is a diagram showing the, current 'through the selenium crystal of the Wheat stone bridge of Fig-.1 during changes-of illumination and the corresponding current f through the indicator circuit;

pfFigp3-shows a simple formotcircuit which, according to this invention, it is 7 proposed to substitute for that shown in indicator circuit. This circuit is made to} produce a continuous sound in. the telegphone ,receiver by the action" of the inter 50 rupter, the -note emitted depending upon-i the number" of interruptipns. per sg gofidijf When the print is removed, the bridge Figsin, 5 and: 6 are modified forms ofthe il -Which a plurality of circuit arrangements in Figsd: are associated.-

Fig; 7 i a complete forth of the invention I f firing .to Fig. 1, A denotes a selenium or cellwhich constitutes one arm of a Wheatstone bridge, the other arms of which contain resistances B, C and D respectively. A battery E supplies the bridge with current and the indicator circuit com-' prises the telephone receiver G and the interrupter F. This is the Wheatstone bridge arrangement of the Brown optiphone and its operation has been described above. It

is necessary, however, to examine the action of the bridge when the rate ,at which printed matter is passed in front of the duced, as by bringing-*a'portion of a black "rent through the cell.

letter before the crystal, the resistance of the cell increases, first rapidly and then more slowly, causing a corresponding fall of our- This change of current is indicated by the section ab, Fig. 2. This shows the current condition between the time t and the time 25'. If nowthe original illumination is restored from time t to time t the current will rise, as indicated by the portion 1) 0 of the curve, the bridge being restored to the balanced condition. The remaining portion of the curve, a m, repre-' vsents slmilar changes in the current through the selenium' but with more rapid and less regular movementof the print in front of the cell. The portions 0 d, and d e of the curve, show respectively the current fall and rise during the relatlvely short intervals from t to t and t to t. tion is now reduced over the eriod from t to t and thenis increased during the period from t to t", the current will fall from the point e to the point It and will then rise to the point z, the latter interval being too short to allow the current to reach the steady value H, so that the bridge will remain in the unbalanced condition. If now the succeeding intervals are likewise short, as shown by the portion of the curve between 2 and m, the bridge will remain unbalanced. This is indicated by the curve a m (Fig. 2) which shows the changes of current in the indicator circuit corresponding to those through the selenium cell. The

bridge is balanced when this current is zeroand unbalanced when the current has any other value. It is therefore unbalanced during the interval from t to t", the tone heard in the receiver varying in intensity as the rate of movement of the print is varied.

It is seen, therefore, that if the bridge is thrown into an unbalanced condition as represented at 72- of Fig. 2 and the print is then rapidly moved past the crystal, the bridge will remain unbalanced and a continuous If the illuminaindicator circuit controlled. by the relay R- and containing a battery E, a. telephone receiver G and an interrupter F. A portion Q of the winding of relay R is shunted through variable resistance'D and a circuit interrupter S also controlled by the relay R.

The whole of the winding of relay R may be shunted, rather than the portion Q, if desired. The armatures -K and K are held against adjustable contacts O'and' v by adjustable springs T and T, respectively. An additional spring carrying a contact S is provided, as shown, though a stationary contact may be used ifthe fall of current through the relay is sufliciently rapid to prevent chattering. The position of contact S may be adjusted by means of the adjustable stop P. a

The function of the circuit AER is similar to that of thecircuit ABCDE of Fig. 1, and

the indicator circuit OF GE performs, in general, the same function as the indlcator circuit FG of Fig. 1. There is the difler-' ence. however, that the indicator circuit OFGE" is positively made and broken, by properly proportioning the strength of battery E or the number of turns of the relay R, while the indicator circuit FG of F1g. 1 is conductively connected to the control c1rcuit at all times. The momentat which the armature K will be attracted, as the current in the control circuit rises, may be determined by adjustment of the control circuit or by tension of the springs or the size of air gap between armature K and the core of relay R. The curve Hm of Fig. 2 represents the current inthe control circuit of Figs. 3 to 6 as well as Fig. 1.

The operation of the arrangement of Flg. 3 is as follows: Suppose that the control circuit is so adjusted that the armature K will be attracted when the point I) of the curve, of Fig. 2. is reached. Since the straight line 6 a intersects each portion of the curve which represents a rising current, the indicator circuit will be opened during each rise 'of current. If now the indicator j be released until the current reachesa value much lower than that at which-the armature was attracted when the currentrose, with: out the provis onlof special means te-accomplish this purposeiThis-is due to the fact that the. armature K in ts circuitclosing position iS -f.at- -S0me distance from the core of therelay Rgand hence the attraction is less than when the armature isin contact with the'core of the relay. I

Suppose, for example, that the current must fall to a value as low as that indicated by point a Fig. 2, before the armature K .is released. The result will be that the armature will-not be released 'between the points I)? and m of the current in the control circuit, since the points d, h, m'lie aboye the point a The purpose of the shunt clr- .cuit around a portion or all. of thewindings of the relay R is toadvance the point at which the armature will be released when the current is 'falling. Itis, desirable,

although not essential, that the resistance 1) be adjustedruntil the point of release falls upon the line c n, thatis, untilthe value of ground is moved past the crystal, the resistance of the cell is varied, causing a corresponding rise and fall of the current in the control circuit, as indicated by the curve Hm: of Fig. 2. The value of the illumination is normally such as to maintain the armature K in'the position to open the indicator circuit andthe armature K. in the position'to close the shunt circuit DS. Only a portion of the windings of the relay R, therefore, or a portion of the current in the control circuit, is effective to maintain the armature K in this position. By adjusting the resistance D the point of release of-the armature K can be made anything desired within certain limits. When the current falls to the point a of the curve, Fig. 2, as-

sumin that theapparatus-has'been adjusted I K. The tone in the telephone'receiver conto ma e this the point of release of the armature K, the in icator circuit isclosed and a characteristic tone is heard in the telephone receiver. An instantlater the current falls to a value Whichpcrmits the release of armature K, opening the shunt circuit DS tinues until the current in the control circuit again rises and reaches the value 12 when the armature K is attracted and the indicator circuit is again opened. This cycleof operations is repeated as long as the illumination upon the selenium is reversed, regardless of the speed of reversal. The con- O and strength e f springs and T andthe position of stop'V may be ad, justedto produce the proper sequence of opening and closing of e'ontactsO and S;

The arrangement shownin Fig. 4. is simi-' ,lar to zth'atiof'Fig'. 3, the resistance D per series with n gized, and a contact P- being provided whereby the resistance D is shunted when the relay R is deenergized. Contact points S and P are so adjusted that, when the re-.

lay is energized, the contact P remains closed untilafter contact between K and S is made. The function of the resistance D is to compensate for the decrease of resistance in the control circuit brought about by theoperation of the shunt about coil Q. The operation of the arrangement of Fig.

4 is the same as that of Fig; 3, except that immediately after the shunt circuit PSK is made the resistance D, normally shuntedthrough the contact P, is thrown into the Referring to Figs. 5 and 6, alternative arrangements are shown in which an auxiliary relay N and an auxiliary battery E are the'zfunction of resistance D of 'secondgresistance D being in the relay whenthe same is ener- L used. In each of these figures the relay N is short-circuited through the contact S when the current through the relay R reaches the value which will cause the at-- the relay R, which is included in circuit with the battery E.- In Fig; 6 the battery E" is connected directly in shunt to .the relay It through the contact. point P. In

practicethe armatures K, K" and K of Figs. 5.and 6 are provided with adjustable stops and springs similar to those shown by way of example in Figs. 3 and 4.

The operation of Fig. 5 is as follows energized, the

Normally, the relay R is, armatures K and K being attracted: The relay N is therefore short-circuited and the circuit of battery E is opened. If now the illumination upon the. selenium crystal A is decreased, the current in the control circuit AER will decrease until a point is reached at moving part, which upon release would first open contact S and upon completion of swing would close contact 0.

In Fig. 6 the battery E performs the same function as the corresponding battery E in Fig. 5, theauxiliary magnetizing effect being produced by current flowing directly through the coils of the main winding of relay R. The operation of this figure will therefore be understood from the description of that of Fig. 5.

While this invention is capable of general use as a relay system, a single selenium cell and control circuit and indicator circuit be.- mg used, it is designed more particularly foruse with a plurality of thesecircuits in a manner analogous to the use of a plurality of Wheatstone bridge circuits of the Brown optiphone, which is described above. This arrangement is indicated diagrammatically in Fig. 7, in which the circuits of Fig. 4 are shown 'as triplicated, by way of example. The three selenium cells A are placed in proximity to each other and alined. A single telephone receiver G having three separate coils, one for each indicator circuit, is shown. The interrupters F, F, F inter rupt their respective circuits at difl'erent rates.

In the use of this form of optiphone, as in that of Brown, the apparatus would be assembled-in a suitablecase adapted, if desired, to be held in the hand of the user. It

- is sometimes found desirable to employ a 3 lens with the selenium crystals to focus the light thereon, as in. the Brown system.

The invention, when applied to relaycircuits, is not necessarily limited to the use with a light-sensitive element in the "control circuit, since obviously the circuit arrangements disclosed would be of use with any current-varying device. Whlle varlous -'c1rcu1t arrangements embodying the broad principles of the invention have been shown and described, it is to be understood that other arrangements besides those specifically shown and described may be employed for accomplishing the same or similar purposes without departing from the spirit and scope ofthe invention, which is defined in the claims.

What is claimed is:

1. An optiphone'comprising a light-sensitive element and means for causing a signal indication for each change of current through the light-sensitive element independently of the rate of change or the duration of illumination upon said light-sensitive element. g

2; An optiphone comprising a light sensitive element and means for causing a signal indication for each change of current through the light-sensitive element, said means including a relay having an armature, and means for advancing the point of release of the relay armature when the current through the light-sensitive element is falling.

3. An optiphone comprising means for causing a signal indication for each change of current through the light-sensitive element thereof, said means including a relay, and means for causing the relay to release its armature when the current through the light-sensitive element falls to the value at which the armature is attracted when the current is rising.

4. In a signaling system, the combination with a light-sensitive resistance elementyof a circuit therefor,- a source of current and a relay in said circuit, an indicator circuit controlled by said relay, and means associated with said relay for causing it to release when the current in said circuit in falling reaches that value at which the armature is attracted when the current is rising. Q

5. In a signaling system, the combination with a light sensitive resistance element, of a circuit therefor, a source of current in said circuit, a relay controlled by said circuit, an indicator circuit controlled by the armature of said relay, and means controlled by said relay for shunting a portion of the windings thereof, whereby the point of release of said armature is advanced and the current in the indicator circuit is made to follow the changes of illumination upon said light sensitive resistance element with substantial fidelity. I

6. In a signaling system, the combination with a light-sensitive resistance element, of a circuit therefor, a source of current in said circuit, a relay controlled by said circuit, an indicator circuit controlled by the arma; ture of said relay, and means controlled by said relay for'hastening the releaseof sa d armature when the current through said light-sensitive element is decreasing, the operation of said last-mentioned means aifecting the current through said light-sensitive element, and means for compensating in part at least for the change in current thus produced.

7. In a signaling system, the combmatlon with a control circuit. of a source of current therein, means in said circuit for varying the strength of current therein, a relay controlled by said control circuit, the armature of which controls an indicator circuit, means controlled by said relay for hastening the release ofsaid armature when the current pensating in part at least for the change in in current thus produced.

8. In a -relay system, a circuit, a relay.

therein, means includinga light-sensitive element and a source of electromotive force tem comprising a circuit, a relay therein, and

a light-sensitive element for causing the current in said relay to rise and fall, which method includes causing the relay to release when the current in said circuit in falling reaches that value at which. the armature is attracted When the current is rising.

10. The method of operating an optiphone comprising a circuit, a source of current and a light-sensitive resistance element therein, and an indicator circuit controlled by said first-mentioned circuit, which method comprises the moving of characters to be interpreted relatively to the light-sensitive element and adjacent thereto and in such a manner as to prevent the current through said element from returning to its normal value during a plurality of reversals of illumination of sald element, and causing the rise and fall of current in the indicator cir-' cuit to lag behind the current variation in a light-sensitive resistance element'therein,

and an indicator circuit controlled by said first-mentioned circuit, which'method com-' prises the moving of characters to be interpreted relatively to the light-sensitive element and adjacent thereto and in such a manner as to prevent the current through said element fronmreturning to its normal value during a plurality of reversals of illumination of said element, and causin the time of beginning of current change in the indicator circuit to vary from that in the first-mentioned circuit.

12. The method of operating an o'ptiphone comprising a circuit and a source of current and a light-sensitive resistance element therein, which method includes the moving of characters to be interpreted relatively to the light-sensitive element and adjacent thereto and in such a manner as to prevent the current through said elementfrom returning to its normal value during a plurality of reversals of illumination of said element, and.

causing; each variation of current through the light-sensitive element away from the normal current value therethrough to initiate a signal indication.

In witness whereof, I hereunto subscribe my nam this 18th day of October A. D.,

' WILLIAM G. HOUSKEEPER. 

